The present invention relates generally to polymeric compositions and a variety of articles that can be formed using such polymeric compositions, e.g., for incorporation in communications cables.
A broad range of electrical cables and buffered optical fibers cables are installed in modern buildings for a wide variety of uses. These cables are used, for example, to provide data transmission between computers, voice communications, as well as control signal transmission for building security, fire alarms, and temperature control systems. Cable networks extend throughout modern office and industrial buildings, and frequently extend through the space between the dropped ceiling and the floor above.
Ventilation system components are also frequently extended through this space for directing heated and chilled air to the space below the ceiling and also to direct return air exchange. The space between the dropped ceiling and the floor above is commonly referred to as the plenum area. Electrical cables and fiber optic cables extending through plenum areas are governed by special provisions of the National Electric Code (“NEC”).
The cable standards are increasing the required maximum frequencies supported by communications cables from 100-200 MHz to 250-1000 MHz. Recently, 40 Gbts transmission of data over copper cables has been proposed. The maximum upper frequency of a cable is that frequency at which the attenuation/cross-talk ratio (“ACR”) is approximately equal to 1. Since signal strength decreases with frequency and data attenuation and cross-talk increases with frequency, the design of cables that would support high frequencies poses a significant challenge. This is especially true since many conventional designs for cable components, e.g., fillers and spacers, may not provide sufficient cross-talk isolation at the higher frequencies.
The selection of materials for forming cables that can support high frequencies and concurrently exhibit favorable flame and smoke characteristics can be challenging. Accordingly, there remains a need for enhanced materials for use in fabricating various components of communications cables such that the cables would exhibit desired properties, e.g., for high-speed transmission of data.